Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

/*
TASK: CFC
LANG: JAVA
 */
public class CFC {
    static int n , m , zi , zj , sum;
    static int min;
    static int[][] grid;
    static boolean[][] seen;
    static int[] r , c;
    static boolean[] rF , cF;
    static int rS , cS;

    public static void main(String[] args) throws IOException {
        FastScanner in = new FastScanner(System.in);
        min = 501;
        n = in.nextInt();
        m = in.nextInt();
        grid = new int[n][m];
        seen = new boolean[n][m];
        r = new int[n];
        c = new int[m];
        rF = new boolean[n];
        cF = new boolean[m];
        for(int i = 0; i < n; i++){
            for(int j = 0;j < m; j++){
                grid[i][j] = in.nextInt();
                if(grid[i][j] == 0){
                    zi = i;
                    zj = j;
                }
                min = Math.min(min , grid[i][j]);
            }
        }
        if(min > 0){
            if(n < m){
                rS = min;
                sum += min*n;
                for(int i = 0; i < n;i++){
                    for(int j = 0;j < m;j++){
                        grid[i][j] -= min;
                        if(grid[i][j] == 0){
                            zi = i;
                            zj = j;
                        }

                    }
                }
            }
            else{
                sum += min*m;
                cS = min;
                for(int i = 0; i < n;i++){
                    for(int j = 0;j < m;j++){
                        grid[i][j] -= min;
                        if(grid[i][j] == 0){
                            zi = i;
                            zj = j;
                        }
                    }
                }
            }
        }
        rF[zi] = true;
        cF[zj] = true;
        dfs(zi , zj);
        System.out.println(sum);
        if(rS > 0){
            for(int i = 1; i <= n; i++){
                for(int j = 0;j < rS; j++){
                    System.out.println("row " + i);
                }
            }
        }
        else if(cS > 0){
            for(int i = 1; i <= m; i++){
                for(int j = 0;j < cS; j++){
                    System.out.println("col " + i);
                }
            }
        }
        for(int i = 0; i < n; i++){
            if(r[i] > 0){
                for(int j = 0;j < r[i]; j++){
                    System.out.println("row " + (i+1));
                }
            }
        }
        for(int i = 0; i < m; i++){
            if(c[i] > 0){
                for(int j = 0;j < c[i]; j++){
                    System.out.println("col " + (i+1));
                }
            }
        }
    }
    public static void dfs(int i , int j){
        if(seen[i][j])return;
        seen[i][j] = true;
        int k = grid[i][j] - (r[i] + c[j]);
        if(k < 0){
            System.out.println(-1);
            System.exit(0);
        }
        if(rF[i] && cF[j]){
            if(k != 0){
                System.out.println(-1);
                System.exit(0);
            }
        }
        if(rF[i]){
            c[j] += k;
            sum += k;
            cF[j] = true;
        }
        else if(cF[j]){
            r[i] += k;
            sum += k;
            rF[i] = true;
        }
        if(i < n-1) dfs(i+1 , j);
        if(i > 0) dfs(i-1 , j);
        if(j < m-1) dfs(i , j+1);
        if(j > 0) dfs(i , j-1);

    }
    private static class FastScanner {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public FastScanner(InputStream stream) {
            this.stream = stream;
        }

        int read() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) return -1;
            }
            return buf[curChar++];
        }

        boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        boolean isEndline(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String next() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public String nextLine() {
            int c = read();
            while (isEndline(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndline(c));
            return res.toString();
        }
    }
}